Secretion from the parotid gland is controlled by both branches of the autonomic nervous system. The responsiveness of the secretory cells is determined to some extent by the degree to which they have been activated. This system is being used to study the extent to which the differentiation of these secretory cells also is regulated by the autonomic nerves. Molecular and physiological markers of the secretory events will be studied during development and after perturbation of the normal innervation patterns in the rat to assess the role of the sympathetic and para-sympathetic nerves in this process. Octopamine concentrations during development and effects on secretory events will also be monitored to see if it has a role in development.